Virgin Group founder Richard Branson has suspended a $1 billion investment mission with Saudi Arabia because of the disappearance of Washington Post columnist Jamal Khashoggi.

Branson made the announcement Thursday as U.S. senators sparked an investigation into the cases surrounding the thriller of the missing U.S. resident and Saudi critic.

“What has reportedly happened in Turkey around the disappearance of journalist Jamal Khashoggi, if proved true, would clearly change the ability of any of us in the West to do business with the Saudi Government,” Branson stated in a commentary.

“We have asked for more information from the authorities in Saudi and to clarify their position in relation to Mr Khashoggi.”